Eating out is the biggest pain we find, this time of year we always take picnics, much easier than being restricted to the one very plain option. Although DS loves Pizza Hut's spag bol so life is not all bad.
Picnic food we have: plain crisps, olives, hummus, nuts and nut butters, ham, sausages, tomatoes, bread, oatcakes, fruit, dark chocolate, homemade cake (DS is only allergic to raw egg thankfully so cake is easy), haribou, fruit juice.
Yes, yes to jus roll pastry being a life saver, and you can get dairy free chocolate-nut spread (which advertises itself as gluten free, which makes no sense since all nutella is gluten free). Marshmallows are egg free (unless homemade). Low fat McVities Digestives are dairy and egg free I think (normal ones aren't). Puddings are the biggest pain we find.